/usr/share/gauche-0.9/0.9.4/lib/www/css.scm is in gauche 0.9.4-6.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 | ;;;
;;; css.scm - Generate and parse CSS
;;;
;;; Copyright (c) 2014 Shiro Kawai <shiro@acm.org>
;;;
;;; Redistribution and use in source and binary forms, with or without
;;; modification, are permitted provided that the following conditions
;;; are met:
;;;
;;; 1. Redistributions of source code must retain the above copyright
;;; notice, this list of conditions and the following disclaimer.
;;;
;;; 2. Redistributions in binary form must reproduce the above copyright
;;; notice, this list of conditions and the following disclaimer in the
;;; documentation and/or other materials provided with the distribution.
;;;
;;; 3. Neither the name of the authors nor the names of its contributors
;;; may be used to endorse or promote products derived from this
;;; software without specific prior written permission.
;;;
;;; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
;;; "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
;;; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
;;; A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
;;; OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
;;; SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
;;; TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
;;; PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
;;; LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
;;; NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
;;; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
;;;
;; EXPERIMENTAL : API may change
(define-module www.css
(use gauche.generator)
(use gauche.lazy)
(use parser.peg)
(use util.match)
(use text.tree)
(use srfi-13)
(export construct-css simple-selector?
css-parse-file
css-parse-selector-string)
)
(select-module www.css)
;;;
;;; S-expression CSS
;;;
;;; <s-css> : {<ruleset> | <at-rule>} ...
;;; <style-rule> : (style-rule <pattern> <declaration> ...)
;;; | (style-decls <declaration> ...)
;;;
;;; <pattern> : <selector> | (or <selector> ...)
;;; <seletor> : <simple-selector>
;;; | <chained-selector>
;;; <chained-selector> : (<simple-selector> . (<op>? . <chained-selector>))
;;; <op> : > | + | ~
;;; <simple-selector> : <element-name>
;;; | (<element-name> <option> ...)
;;; <option> : (id <name>) ; E#id
;;; | (class <ident>) ; E.class
;;; | (has <ident>) ; E[attrib]
;;; | (= <ident> <attrib-value>) ; E[attrib=val]
;;; | (~= <ident> <attrib-value>) ; E[attrib~=val]
;;; | (:= <ident> <attrib-value>) ; E[attrib|=val]
;;; | (*= <ident> <attrib-value>) ; E[attrib*=val]
;;; | (^= <ident> <attrib-value>) ; E[attrib^=val]
;;; | ($= <ident> <attrib-value>) ; E[attrib$=val]
;;; | (:not <negation-arg>) ; E:not(s)
;;; | (: <ident>) ; E:pseudo-class
;;; | (: (<fn> <ident> ...)) ; E:pseudl-class(arg)
;;; | (:: <ident>) ; E::pseudo-element
;;; <element-name> : <ident> | *
;;; <attrib-value> : <ident> | <string>
;;; <negation-arg> | <element-name> | * | <option> ; except <negation-arg>
;;;
;;; <declaration> : (<ident> <expr> <expr2> ... <important>?)
;;; <important> : !important
;;; <expr> : <term>
;;; | (/ <term> <term> ...)
;;; | (or <term> <term> ...)
;;; | #(<term> <term> ...) ; juxtaposition
;;; <term> : <quantity> | (- <quantity>) | (+ <quantity>)
;;; | <string> | <ident> | <url> | <hexcolor> | <function>
;;; <quantity> : <number>
;;; | (<number> %)
;;; | (<number> <ident>)
;;; <url> | (url <string>)
;;; <hexcolor> | (color <string>) ; <string> must be hexdigits
;;; <function> | (<fn> <arg> ...)
;;; <arg> | <term> | #(<term> ...) | (/ <term> <term> ...)
;;;
;;;
;;; NB: style-decls shouldn't appear in a complete stylesheet, but can
;;; appear when the 'style' attribute of the document is parsed.
;;; It is also useful to render the value for the style attribute.
;;;
;;; NB: Negaton op is :not instead of not, since (not <negation-arg>)
;;; would be ambiguous from the simple node named "not" with one option.
;;
;; Some utilities on S-expr CSS
;;
;; API
;; Returns canonicalized simple selector (element . options) or #f
(define (simple-selector? sel)
(define (option? x)
(match x
[(a b . _) (memq a '(id class has = ~= := *= ^= $= :not : ::))]
[_ #f]))
(match sel
[(? symbol?) (list sel)]
[((? symbol?) (? option?) ...) sel]
[_ #f]))
;;
;; S-expr CSS -> CSS
;;
;; API
(define (construct-css sexpr :optional (oport (current-output-port)))
(define (render top)
(match top
[('style-rule pattern . decls)
(write-tree (render-style-rule pattern decls) oport)
(newline oport)]
[('style-decls . decls)
(write-tree (intersperse ";" (map render-decl decls)))]
[_ (error "invalid or unsupported sexpr css:" top)]))
(define (render-style-rule pattern decls)
`(,(render-pattern pattern) "{"
,(intersperse ";" (map render-decl decls))
"}\n"))
(define (render-pattern pattern)
(match pattern
[('or selector ...) (intersperse "," (map render-selector selector))]
[_ (render-selector pattern)]))
(define (render-selector selector)
(if-let1 s (simple-selector? selector)
(render-simple-selector s)
(let loop ([sels selector])
(cond [(null? sels) '()]
[(simple-selector? (car sels))
=> (^s `(,(render-simple-selector s)" " ,@(loop (cdr sels))))]
[(memq (car sels) '(> + ~)) `(,(car sels) ,@(loop (cdr sels)))]
[else (error "invalid selector in sexpr css:" selector)]))))
(define (render-simple-selector s)
`(,(car s) ,@(map render-options (cdr s))))
(define (render-options op)
(match op
[('id name) `("#" ,name)]
[('class name) `("." ,name)]
[('has name) `("[" ,name "]")]
[((and (or '= '~= '^= '$= '*=) op) ident value)
`("[" ,ident ,op ,(render-attrval value) "]")]
[(':= ident value) `("[" ,ident "|=" ,(render-attrval value) "]")]
[(':not not-arg) `(":(" ,(if (symbol? not-arg)
not-arg
(render-options not-arg)) ")")]
[(': (fn arg ...)) `(":" ,(render-fn fn arg))]
[(': ident) `(":" ,ident)]
[(':: ident) `("::" ,ident)]
[_ (error "invalid selector option:" op)]))
(define (render-attrval val) (if (string? val) (escape-string val) val))
(define (escape-string val)
(if (string-index val #\')
`(#\",(regexp-replace-all* val #/\"/ "\\22") #\")
`(#\',val #\')))
(define (render-fn fn args)
`(,fn "(" ,@(intersperse "," (map render-arg args)) ")"))
(define (render-arg arg)
(match arg
[#(v ...) (intersperse " " (map render-attrval v))]
[(/ v ...) (intersperse "/" (map render-attrval v))]
[v (render-attrval v)]))
(define (render-decl decl)
(match decl
[(ident expr . exprs)
(if (and (pair? exprs)
(eq? (last exprs) '!important))
`(,ident ":" ,@($ intersperse " " $ map render-expr
$ cons expr (drop-right exprs 1))
" !important")
`(,ident ":" ,@($ intersperse " " $ map render-expr
$ cons expr exprs)))]
[_ (error "invalid declaration:" decl)]))
(define (render-expr expr)
(match expr
[('/ term ...) (intersperse "/" (map render-term term))]
[('or term ...) (intersperse "," (map render-expr term))]
[#(term ...) (intersperse " " (map render-expr term))]
[term (render-term term)]))
(define (render-term term)
(match term
[('- quantity) `(- ,(render-quantity quantity))]
[('+ quantity) `(+ ,(render-quantity quantity))]
[('color digs) `("#" ,digs)]
[#(expr ...) (intersperse " " (map render-expr expr))]
[((? number?) x) (render-quantity term)]
[((? symbol? fn) expr ...)
`(,fn "(" ,@(intersperse "," (map render-expr expr)) ")")] ;also url
[(? string?) (escape-string term)]
[(? symbol?) term]
[(? number?) term]
[_ (error "invalid term:" term)]))
(define (render-quantity quant)
(match quant
[(num '%) `(,num "%")]
[(num unit) `(,num ,unit)]
[num num]))
(for-each render sexpr))
;; experimental
(define ($/ parser . parsers)
(if (null? parsers)
parser
($or ($try parser) (apply $/ parsers))))
;;
;; CSS -> S-expr CSS
;;
;; Core syntax
;; http://www.w3.org/TR/css3-syntax/
;; CSS grammar definition is layered in order to allow different support
;; levels of the client. It's conceptually parallel to Lisp syntax---
;; the S-expression defines the core syntax, and more complex syntax is
;; defined on top of S-expr.
;; The API provides access for the lower layer, with the option to hook
;; a translator for certain syntax units.
;; NB: @charset rule is not handled here; we need to switch port encodings
;; 4.3 Tokenizer
;; css-token-generator :: [Char] -> ( () -> Token )
;; Token = (IDENT . name) | (FUNCTION . name) | (AT-KEYWORD . name)
;; | (HASH name flag) | (STRING . value) | (BAD-STRING)
;; | (URL . value) | (BAD-URL)
;; | (DELIM . char) | (NUMBER . value) | (PERCENTAGE . value)
;; | (DIMENSION value unit)
;; | (UNICODE-RANGE start end)
;; | (INCLUDE-MATCH) | (DASH-MATCH) | (PREFIX-MATCH) | (SUFFIX-MATCH)
;; | (SUBSTRING-MATCH) | (COLUMN) | (WHITESPACE) | (CDO) | (CDC)
;; | (COLON) | (SEMICOLON) | (COMMA) | (OPEN-BRACKET) | (CLOSE-BRACKET)
;; | (OPEN-PAREN) | (CLOSE-PAREN) | (OPEN-BRACE) | (CLOSE-BRACE)
(define %w ($skip-many ($one-of #[ \t\r\n\f])))
(define %s ($skip-many1 ($one-of #[ \t\r\n\f])))
(define %nl ($/ ($s "\n") ($s "\r\n") ($s "\n") ($s "\f")))
;; comment => vlid
(define %comment
($seq ($s "/*")
($skip-many ($none-of #[*]))
($skip-many1 ($c #\*))
($skip-many ($seq ($none-of #[/*])
($skip-many ($none-of #[*]))
($skip-many1 ($c #\*))))
($c #\/)))
;; nonascii [^\0-\237] => char
(define %nonascii ($none-of #[\x00-\x9f]))
;; unicode \\[0-9a-f]{1,6}(\r\n|[ \n\r\t\f])? => char
(define %unicode ($do [ ($c #\\) ]
[code ($many ($one-of #[0-9a-fA-F]) 1 6)]
[ ($optional ($/ ($s "\r\n") ($one-of #[ \n\r\t\f]))) ]
($return ($ integer->char
$ (cut string->number <> 16)
$ list->string code))))
;; escape {unicode}|\\[^\n\r\f0-9a-f] => char
(define %escape ($/ %unicode ($seq ($c #\\) ($none-of #[\n\r\f0-9a-f]))))
;; nmstart [_a-z]|{nonascii}|{escape} => char
(define %nmstart ($/ ($one-of #[_a-zA-Z]) %nonascii %escape))
;; nonascii [^\0-\237] => char
(define %nonascii ($none-of #[\x00-\x9f]))
;; unicode \\[0-9a-f]{1,6}(\r\n|[ \n\r\t\f])? => char
(define %unicode ($do [ ($c #\\) ]
[code ($many ($one-of #[0-9a-fA-F]) 1 6)]
[ ($optional ($/ ($s "\r\n") ($one-of #[ \n\r\t\f]))) ]
($return ($ integer->char
$ (cut string->number <> 16)
$ list->string code))))
;; escape {unicode}|\\[^\n\r\f0-9a-f] => char
(define %escape ($/ %unicode
($seq ($c #\\) ($none-of #[\n\r\f0-9a-f]))))
;; nmstart [_a-z]|{nonascii}|{escape} => char
(define %nmstart ($/ ($one-of #[_a-zA-Z]) %nonascii %escape))
;; nmchar [_a-z0-9-]|{nonascii}|{escape} => char
(define %nmchar ($/ ($one-of #[_a-zA-Z0-9-]) %nonascii %escape))
;; name {nmchar}+ => string
(define %name ($->string ($many1 %nmchar)))
;; ident [-]?{nmstart}{nmchar}* => string
(define %ident ($->symbol ($optional ($c #\-)) %nmstart ($many %nmchar)))
(define %hexdigit ($one-of #[0-9a-fA-F]))
;; num [0-9]+|[0-9]*\.[0-9]+
(define %num
(let* ([digs ($many1 ($one-of #[0-9]))]
[frac ($->rope ($c #\.) digs)])
($lift ($ string->number $ rope->string $)
($/ ($->rope digs ($optional frac))
($->rope frac)))))
;; string {string1}|{string2}
;; string1 \"([^\n\r\f\\"]|\\{nl}|{escape})*\"
;; string2 \'([^\n\r\f\\']|\\{nl}|{escape})*\'
(define %string
($->rope
($/ ($between ($char #\")
($many ($/ ($none-of #[\n\r\f\"\\])
($try ($seq ($char #\\) %nl))
%escape))
($or ($char #\") eof))
($between ($char #\')
($many ($/ ($none-of #[\n\r\f\'\\])
($try ($seq ($char #\\) %nl))
%escape))
($or ($char #\') eof)))))
(define %bad-string
($/ ($seq ($char #\")
($skip-many ($/ ($none-of #[\n\r\f\"])
($try ($seq ($char #\\) %nl))
%escape))
($char #\newline))
($seq ($char #\')
($skip-many ($/ ($none-of #[\n\r\f\'])
($try ($seq ($char #\\) %nl))
%escape))
($char #\newline))))
(define %url
($lift (^[_ _ r _ _] (rope->string r))
($string "url(") %w
($->rope ($/ %string
($many ($/ ($one-of #[!#$%&*-~])
%nonascii
%escape))))
%w ($char #\))))
(define %unicode-range
(letrec [(code (^[cs] (string->number (list->string cs) 16)))]
($seq ($one-of #[Uu]) ($c #\+)
($/ ($lift (^[cs1 _ cs2] `(UNICODE-RANGE ,(code cs1) ,(code cs2)))
($many %hexdigit 1 6) ($c #\-) ($many %hexdigit 1 6))
($do [ds ($many %hexdigit 1 5)]
[ws ($many ($c #\?) 1 (- 6 (length ds)))]
($return
`(UNICODE-RANGE ,(code (append ds (map (^_ #\0) ws)))
,(max (code (append ds (map (^_ #\f) ws)))
#x10ffff))))
($lift (^[cs] `(UNICODE-RANGE ,(code cs) ,(code cs)))
($many %hexdigit 1 6))))))
;; Tokenizer
;; comment returns :comment, which is ignored by the token generator
;; note that this parser never fails except at the end of input.
(define %tokenize
($/ ($seq %comment ($return :comment))
($seq %s ($return '(WHITESPACE)))
%unicode-range
($seq ($s "~=") ($return '(INCLUDE-MATCH)))
($seq ($s "|=") ($return '(DASH-MATCH)))
($seq ($s "^=") ($return '(PREFIX-MATCH)))
($seq ($s "$=") ($return '(SUFFIX-MATCH)))
($seq ($s "*=") ($return '(SUBSTRING-MATCH)))
($seq ($s "||") ($return '(COLUMN)))
($seq ($s "<!--") ($return '(CDO)))
($seq ($s "-->") ($return '(CDC)))
($seq ($c #\:) ($return '(COLON)))
($seq ($c #\;) ($return '(SEMICOLON)))
($seq ($c #\,) ($return '(COMMA)))
($seq ($c #\[) ($return '(OPEN-BRACKET)))
($seq ($c #\]) ($return '(CLOSE-BRACKET)))
($seq ($c #\() ($return '(OPEN-PAREN)))
($seq ($c #\)) ($return '(CLOSE-PAREN)))
($seq ($c #\{) ($return '(OPEN-BRACE)))
($seq ($c #\}) ($return '(CLOSE-BRACE)))
($lift (^[val] `(URL . ,val)) %url)
($lift (^[ident _] `(FUNCTION . ,ident)) %ident ($c #\())
($lift (^[ident] `(IDENT . ,ident)) %ident)
($lift (^[_ ident] `(AT-KEYWORD . ,ident)) ($c #\@) %ident)
($lift (^[_ val] `(HASH ,val #t)) ($c #\#) %ident)
($lift (^[_ val] `(HASH ,val #f)) ($c #\#) %name)
($lift (^[val] `(STRING . ,val)) %string)
($lift (^[_] '(BAD-STRING)) %bad-string)
($lift (^[val _] `(PERCENTAGE . ,val)) %num ($c #\%))
($lift (^[val unit] `(DIMENSION ,val ,unit)) %num %ident)
($lift (^[val] `(NUMBER . ,val)) %num)
($do [c anychar] ($return `(DELIM . ,c)))))
(define (css-token-generator chars)
(define cs chars)
(rec (gen)
(if (null? cs)
(eof-object)
(receive (val next) (peg-run-parser %tokenize cs)
(set! cs next)
(if (eq? val :comment) (gen) val)))))
(define (css-tokenize chars)
(generator->lseq (css-token-generator chars)))
;;
;; 5. Core parser
;;
;; Accept token of specific type
(define ($tok type)
(^s
(cond [(null? s) (return-failure/expect type s)]
[(eq? (caar s) type) (return-result (cdar s) (cdr s))]
[else (return-failure/expect type s)])))
(define ($delim char)
(^s
(cond [(null? s) (return-failure/expect char s)]
[(and (eqv? (caar s) 'DELIM) (eqv? (cdar s) char))
(return-result (cdar s) (cdr s))]
[else (return-failure/expect char s)])))
(define (%preserved-token s)
(if (null? s)
(return-failure/unexpect "EOF" s)
(return-result (car s) (cdr s))))
(define %WS* ($skip-many ($tok 'WHITESPACE)))
(define %component-value
($lazy
($between %WS*
($/ %brace-block %paren-block %bracket-block %function-call
%preserved-token)
%WS*)))
(define (block-parser opener closer tag)
($lift (^[_ _ v _] `(,tag ,@v))
($tok opener) %WS*
($many ($seq ($not ($tok closer)) %component-value))
($tok closer)))
(define %brace-block (block-parser 'OPEN-BRACE 'CLOSE-BRACE 'brace-block))
(define %paren-block (block-parser 'OPEN-PAREN 'CLOSE-PAREN 'paren-block))
(define %bracket-block (block-parser 'OPEN-BRACKET 'CLOSE-BRACKET 'bracket-block))
(define %function-call
($lift (^[fn args _] `(funcall ,fn ,@args))
($tok 'FUNCTION)
($many ($seq ($not ($tok 'CLOSE-PAREN)) %component-value))
($tok 'CLOSE-PAREN)))
(define %at-rule
($lift (^[keyword _ args block] `(,keyword ,args ,block))
($tok 'AT-KEYWORD) %WS*
($many ($seq ($not ($tok 'OPEN-BRACE))
($not ($tok 'SEMICOLON))
%component-value))
($/ %brace-block ($tok 'SEMICOLON))))
(define %qualified-rule
;; NB: We preserve whitespaces between qualifiers, for it is
;; required to parse selectors; see below.
($lift (^[_ words block _] (list words block))
%WS*
($many ($seq ($not ($tok 'OPEN-BRACE))
($/ %paren-block %bracket-block %function-call
%preserved-token ($tok 'WHITESPACE))))
%brace-block %WS*))
(define %important
($do [ ($delim #\!) ]
[ %WS* ]
[v ($tok 'IDENT)]
(if (string-ci=? (symbol->string v) "important")
($return '!important)
($fail "!important expected"))))
(define %declaration
($lift (^[name _ _ block important _] (list name block important))
($tok 'IDENT) %WS* ($tok 'COLON)
($many ($seq ($not ($tok 'SEMICOLON))
($not ($delim #\!))
%component-value))
($optional %important)
%WS*))
(define %declaration-list
($lazy
($seq %WS* ($/ ($sep-by ($optional %declaration) ($tok 'SEMICOLON))
($lift list %at-rule %declaration-list)))))
(define %inter-rule-spaces
($skip-many ($/ ($tok 'CDO) ($tok 'CDC) ($tok 'WHITESPACE))))
(define %rule-list
($many ($/ ($tok 'WHITESPACE) %qualified-rule %at-rule)))
;;
;; Higher-level parser
;;
;; The core syntax defined in section 5 of css3 spec is very tolerable---
;; it accepts variety of syntaxes that doesn't make sense at all. This
;; layer uses higher-level semantics to get a meaningful representation.
;; Selector syntax
;; http://www.w3.org/TR/css3-selectors/
(define %attr-selector-internal
($lift (^[_ name _ opval _]
(if opval `(,(car opval) ,name ,(cdr opval)) `(has ,name)))
%WS* ($tok 'IDENT) %WS*
($optional
($lift (^[op _ val] (cons op val))
($/ ($seq ($delim #\=) ($return '=))
($seq ($tok 'INCLUDE-MATCH) ($return '~=))
($seq ($tok 'DASH-MATCH) ($return ':=))
($seq ($tok 'PREFIX-MATCH) ($return '^=))
($seq ($tok 'SUFFIX-MATCH) ($return '$=))
($seq ($tok 'SUBSTRING-MATCH) ($return '*=)))
%WS*
($/ ($tok 'IDENT) ($tok 'STRING))))
%WS*))
(define (%attr-selector s)
(match s
[(('bracket-block . content) . rest)
(receive (r v s) (%attr-selector-internal content)
(if (and (parse-success? r)
(null? s))
(return-result v rest)
(return-failure/message "attr-selector" s)))]
[_ (return-failure/message "attr-selector" s)]))
(define %class-selector
($lift (^[_ class] `(class ,class)) ($delim #\.) ($tok 'IDENT)))
(define %id-selector
($do [hashval ($tok 'HASH)]
(if (cadr hashval) ; hashval is ident
($return `(id ,(car hashval)))
($fail "identifier required for id selector"))))
(define %pseudo-fn-arg
;; NB: To support an+b syntax
($/ ($tok 'DIMENSION)
($tok 'NUMBER)
($tok 'STRING)
($tok 'IDENT)))
(define %negation-selector-arg
($lazy
($/ %type-selector %attr-selector %class-selector %id-selector
%pseudo-selector)))
;; NB: negation-selector is also treated in pseudo-fn
(define (%pseudo-fn s)
(match s
[(('funcall name . arg-tokens) . rest)
(receive (r v s) (if (eq? name 'not)
(%negation-selector-arg arg-tokens)
(%pseudo-fn-arg arg-tokens))
(if (and (parse-success? r)
(null? s))
(return-result (list name v) rest)
(return-failure/message "pseudo-fn" s)))]
[_ (return-failure/message "pseudo-fn" s)]))
(define %pseudo-selector
($lift (^[_ elem? sel]
(match sel
[('not not-arg) `(:not ,not-arg)]
[(? symbol?) `(,(if elem? ':: ':) ,sel)]
[_ `(,(if elem? ':: ':) ,@sel)]))
($tok 'COLON) ($optional ($tok 'COLON))
($/ ($tok 'IDENT) %pseudo-fn)))
(define %selector-option
($/ %attr-selector
%class-selector
%id-selector
%pseudo-selector))
(define %type-selector
;; TODO: namespace support & case conversion
($/ ($tok 'IDENT) ($seq ($delim #\*) ($return '*))))
(define %simple-selector
($/ ($lift (^[type opts] (if (null? opts) type (cons type opts)))
%type-selector ($many %selector-option))
($lift (^[ops] `(* ,@ops)) ($many1 %selector-option))))
(define %selector-seq
($lazy
($lift (^[sel rest] (if rest (cons sel rest) (list sel)))
%simple-selector
($optional
($try
($lift (^[op rest] (if op (cons op rest) rest))
($/ ($between %WS*
($/ ($seq ($delim #\>) ($return '>))
($seq ($delim #\+) ($return '+))
($seq ($delim #\~) ($return '~)))
%WS*)
($followed-by ($seq ($tok 'WHITESPACE) ($return #f))
%WS*))
%selector-seq))))))
(define %selector-group ;; section 5
($lift (^[sels] (cond [(null? sels) #f]
[(null? (cdr sels)) (car sels)]
[else (cons 'or sels)]))
($sep-by ($lift (^[_ seq _] (if (null? (cdr seq)) (car seq) seq))
%WS* %selector-seq %WS*)
($tok 'COMMA))))
;; TOKENS is the first item of the value of %qualified-rule. Interpret
;; it as a selector and returns <pattern> structure of S-expr CSS.
;; If it can't be parsed, returns #f.
(define (parse-selectors tokens)
(receive (val next) (peg-run-parser %selector-group tokens)
(and (null? next) val)))
;; default declaration value parser
;; This part roughly follows CSS2.1 spec appendix G.
;; The difficulty is in expression;
;; CSS spec dosn't define general precedence among juxtaposition, comma and
;; slash operators, leaving its interpretation to each property. However,
;; the current defined property seems to use this rule:
;; - A rule of thumb is that '/' > juxtaposition > ','
;; - For some shorthand properties, '/' > ',' > juxtaposition
;; TODO: We need another rule for the argument of 'calc'.
(define (%function-expr s)
(match s
[(('funcall name . arg-tokens) . rest)
(receive (r v s) (%comma-separated-exprs arg-tokens)
(if (and (parse-success? r)
(null? s))
(return-result (cons name v) rest)
(return-failure/expect "list of function arguments" s)))]
[_ (return-failure/expect "list of function arguments" s)]))
(define %term
($/ ($lift (^[u qual] (if u `(,(string->symbol (string u)) ,qual) qual))
($optional ($/ ($delim #\+) ($delim #\-)))
($/ ($tok 'NUMBER)
($lift (^[val] `(,val %)) ($tok 'PERCENTAGE))
($tok 'DIMENSION)))
($tok 'STRING)
($tok 'IDENT)
($lift (^[v] `(url ,v)) ($tok 'URL))
($lift (^[v] `(color ,(x->string (car v)))) ($tok 'HASH))
%function-expr))
(define %term-/
($lift (^[a b] (if b `(/ ,a ,b) a))
%term ($optional ($seq ($delim #\/) %term))))
(define %comma-separated-exprs
($sep-by ($lift (^[v vs] (if (null? vs) v (list->vector (cons v vs))))
%term-/ ($many %term-/))
($tok 'COMMA)))
(define %juxtaposed-exprs
($lift (^[vs] (match vs [(x) x] [xs (list->vector xs)]))
($many ($/ ($lift (^[a _ b] `(/ ,a ,b))
%term ($delim #\/) %term)
($lift (^[v vs] (if (null? vs) v (cons v vs)))
%term ($many ($seq ($tok 'COMMA) %term)))))))
(define *juxta-properties*
'(margin padding
border border-top border-right border-bottom border-left
font list-style pause cue))
(define (%decl-value property)
(if (memq property *juxta-properties*)
%juxtaposed-exprs
($do [exprs %comma-separated-exprs]
($return (match exprs [(x) x] [(xs ...) `(or ,@xs)])))))
;; val :: (property-name . tokens)
(define (parse-declaration val)
(match val
[(name tokens important?)
(receive (r v s) ((%decl-value (car val)) tokens)
(if (and (parse-success? r)
(null? s))
`(,name ,v ,@(cond-list [important? '!important]))
(begin
(css-parser-warn "Ignored unparsable value for property ~s: ~s\n"
(car val) (cdr val))
#f)))]
[_ #f]))
(define (parse-declarations block)
(match block
[('brace-block . component-values)
(receive (vals next) (peg-run-parser %declaration-list component-values)
(and (null? next)
(filter-map parse-declaration vals)))]
[_ #f]))
;; Interpret %qualified-rule as a style-rule and returns <ruleset> structure of
;; S-expr CSS. (section 8.1 of CSS3 sytnax)
;; If it can't be parsed, returns #f.
(define (parse-style-rule selector-tokens block-token)
(let ([selector (parse-selectors selector-tokens)]
[decls (parse-declarations block-token)])
(if (and selector decls)
`(style-rule ,selector ,@decls)
(begin
(unless selector
(css-parser-warn "Ignored unparsable selector: ~s\n"
selector-tokens))
(unless decls
(css-parser-warn "Ignored unparsable declarations block: ~s\n"
block-token))
#f))))
;; Integrated stylesheet parser
(define (make-stylesheet-parser qualified-rule-handler)
($seq %inter-rule-spaces
($many ($followed-by
($/ ($lift (^[a]
(css-parser-warn "Ignored unsupported at-rule: ~s\n"
a)
#f)
%at-rule)
($lift (^[q] (qualified-rule-handler (car q) (cadr q)))
%qualified-rule))
%inter-rule-spaces))))
(define (parse-stylesheet tokens
:key (qualified-rule-handler parse-style-rule))
(receive (r rest)
(peg-run-parser (make-stylesheet-parser qualified-rule-handler) tokens)
(filter identity r)))
;; API
;; TODO: Handle @charset
(define (css-parse-file file :key (encoding #f))
(call-with-input-file file
(^p ($ parse-stylesheet
$ css-tokenize $ generator->lseq $ port->char-generator p))
:encoding (or encoding (gauche-character-encoding))))
;; API
;; A utility function to parse only selector part.
;; We can't simply use parse-selectors, for it assumes the tokens is
;; processed as %qualified-rule.
;; Returns #f if input is unparsable. It is ok that imput has extra
;; blocks; they're ignored.
(define (css-parse-selector-string s)
(receive (r v s) ($ %selector-only $ css-tokenize $ x->lseq s)
(and (parse-success? r)
(parse-selectors v))))
(define %selector-only
($seq %WS*
($many ($seq ($not ($tok 'OPEN-BRACE))
($/ %paren-block %bracket-block %function-call
%preserved-token ($tok 'WHITESPACE))))))
;; TODO: make this customizable
(define css-parser-warn warn)
|